JP2001307955A - Solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor superior in high-frequency response. SOLUTION: A valve metal porous sheet 1 where a dielectric oxidization covering film 3, a solid electrolyte layer 4, and a cathode electrode layer 5 are formed on its one surface is covered with an insulation protection layer 6. A conductor 10 connected respectively with an anode electrode 2 and the cathode electrode layer 5 is allowed to be exposed over at least on one surface of the insulation protection layer 6, and a connection bump 11 is formed on the conductor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor used for various electronic devices, and particularly to a solid electrolytic capacitor on which a semiconductor can be mounted.

[0002]

2. Description of the Related Art As a conventional solid electrolytic capacitor, a valve metal porous body such as aluminum or tantalum is used as an anode element, a dielectric oxide film is formed on the surface thereof, and a functional polymer or manganese dioxide or the like is formed thereon. A solid electrolyte layer was provided, a cathode layer was provided on the outer surface of the solid electrolyte layer, the entire body was molded, and an anode element and terminal electrodes electrically connected to the cathode layer were provided at both ends of the body.

[0003]

The conventional solid electrolytic capacitor described above is a single chip type solid electrolytic capacitor like a resistor and an inductance component, and is mounted on a circuit board and used. .

However, with the recent digitization of circuits, high-frequency responsiveness of electronic components is required. However, solid-state electrolytic capacitors surface-mounted on a circuit board together with semiconductors are inferior in high-frequency responsiveness. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid electrolytic capacitor which eliminates the above-mentioned drawbacks of the prior art and which can directly connect a semiconductor to a bump and has excellent high frequency response.

[0006]

According to a first aspect of the present invention, there is provided a valve metal porous sheet having a dielectric oxide film formed on a surface and a hole surface. An electrode portion is provided, a solid electrolyte layer and a cathode electrode layer are provided on the other surface of the valve metal porous sheet body, and an insulating protective layer is provided on the outer peripheral surface thereof. A solid electrolytic capacitor having a hole extending to the electrode portion and the cathode electrode layer, a conductor electrically connected to each electrode and insulated from the other in the hole, and a connection bump provided on a surface of the conductor. In addition, connection bumps are formed on the surface of the solid electrolytic capacitor, and various chip components such as semiconductors can be mounted on the connection bumps, whereby remarkable improvement in high-frequency response can be achieved.

According to a second aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein an aluminum foil having one surface etched is used as the valve metal porous sheet body. Excellent in properties.

A third aspect of the present invention is the solid electrolytic capacitor according to the first aspect, wherein a sintered body of valve metal powder is used as the valve metal porous sheet body. Can be big.

According to a fourth aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein an unetched surface of the aluminum foil having one surface etched is used as the anode electrode portion. And the number of components can be reduced.

According to a fifth aspect of the present invention, there is provided a solid electrolytic capacitor according to the first aspect, wherein another metal layer formed on an unetched surface of an aluminum foil having one surface etched is used as an anode electrode portion. By selecting the layer, the reliability of connection with the conductor can be increased.

According to a sixth aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein one side of the sintered body of the valve metal powder on which the dielectric oxide film is not formed is used as the anode electrode portion. It can be reduced and inexpensive.

According to a seventh aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein a metal layer formed on one surface of a sintered body of valve metal powder on which a dielectric oxide film is not formed is used as an anode electrode portion. In addition, by selecting a metal layer, reliability of connection with a conductor can be improved.

The invention according to claim 8 is the solid electrolytic capacitor according to claim 1, wherein a functional polymer is used as the solid electrolyte layer, and the capacitor can have a low impedance.

According to a ninth aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein a manganese dioxide layer is used as the solid electrolyte layer. The solid electrolytic capacitor can be reliably produced by an established technique.

According to a tenth aspect of the present invention, there is provided the solid electrolytic capacitor according to the first aspect, wherein the number of connection bumps is equal to or larger than the number of connection bumps of the semiconductor.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG.

FIG. 1 is a perspective view of an embodiment of the solid electrolytic capacitor of the present invention, and FIG. 2 is a sectional view of the solid electrolytic capacitor. 1 and 2, reference numeral 1 denotes a valve metal porous sheet made of a sintered body of valve metal powder such as aluminum foil or tantalum having one surface etched, and 2 denotes an anode provided on one surface of the valve metal porous sheet 1. In the case of an aluminum foil, the anode electrode portion 2 may use the surface that is not subjected to etching treatment as it is, or may be formed by forming another metal layer such as gold, copper, or nickel on the surface that is not subjected to etching treatment. In the case of a sintered body of valve metal powder, the surface of the sintered body where the dielectric oxide film is not formed may be used as it is, or a metal layer such as gold, copper, nickel, tantalum may be sputtered, vapor deposited, etc. It may be formed by the method described above.

Reference numeral 3 denotes a dielectric oxide film formed on the surface and the pore surface by anodizing except for the anode electrode portion 2 of the valve metal porous sheet 1, and 4 denotes a dielectric oxide film The solid electrolyte layer 4 is formed by forming a functional polymer layer such as polypyrrole or polythiophene by chemical polymerization or electrolytic polymerization, or by impregnating with a manganese nitrate solution and thermally decomposing. It can be obtained by forming a manganese dioxide layer.

Reference numeral 5 denotes a cathode electrode layer formed on the solid electrolyte layer 4, which can be formed by attaching a metal foil such as copper or applying a conductive paste on the solid electrolyte layer 4. Reference numeral 6 denotes an insulating protective layer covering the entirety, and is formed by molding using an epoxy resin or the like.

Reference numeral 7 denotes a hole provided in the insulating protective layer 6 on the side of the anode electrode section 2, and 8 denotes an insulating protective layer 6 on the side of the anode electrode section 2, the anode electrode section 2, a valve metal porous sheet 1, a dielectric oxide film. 3,
The holes 7 and 8 are formed in the solid electrolyte layer 4, and are formed by laser processing, etching processing, punching processing, or the like.

An insulating layer 9 is formed on the inner wall of the hole 8. A conductor 10 is formed in each of the holes 7 and 8 by plating of copper or the like. The conductor 10 in the hole 7 is the anode electrode portion 2 and the conductor 10 in the hole 8 is the cathode electrode layer 5 only. Is electrically connected to

Connection bumps 11 made of solder, gold, tin, silver or the like are formed on the exposed surface of the conductor 10 formed in the holes 7 and 8, and the number and the number of the connection bumps 11 are formed. The pitch is equal to or larger than the connection bump of the semiconductor to be mounted later. The number of connection bumps equal to or larger than the number of connection bumps of the semiconductor is such that chip components such as a chip resistor, a chip ceramic capacitor, and a chip inductance can be mounted between the remaining connection bumps 11 after the semiconductor is mounted. is there. On the side and bottom surfaces of the insulating protective layer 6, extraction electrodes 12 and 13 connected to the anode electrode unit 2 and the cathode electrode layer 5, respectively, are formed.

As described above, since a semiconductor or the like can be directly mounted on one surface of the solid electrolytic capacitor, a conductive pattern for routing is not required, and the high-frequency response is remarkably improved.

The use of an aluminum foil having an etched surface on one side as the valve metal porous sheet body 1 can use an aluminum foil of an aluminum electrolytic capacitor which has already been established. One side of the aluminum foil is masked and etched. By performing the treatment, the valve metal porous sheet 1 having desired etching pits can be easily obtained, and the productivity can be improved.

The reason why the sintered body of valve metal powder such as tantalum is used as the valve metal porous sheet 1 is that the obtained capacitance becomes large.

Further, since one side of the sintered body of the aluminum foil or the valve metal powder is used as the anode electrode portion 2, a metal layer as another anode electrode portion 2 is not required, the number of components is small, and the production efficiency is improved. This is advantageous in terms of cost. However, when it is desired to improve the reliability of connection with the conductor 10 formed in the holes 7 and 8, a metal layer such as gold, copper or nickel is formed on one surface of the valve metal porous sheet 1 to form an anode electrode. Part 2
It is desirable that

Further, by using a functional polymer such as polypyrrole or polythiophene as the solid electrolyte layer 4, a solid electrolytic capacitor having a low impedance can be obtained, and the high-frequency response can be further improved. However, as a completely established technique, there is a method of forming manganese dioxide, and it is possible to improve productivity and reliability by adopting a method that is dense and can be freely controlled in thickness.

In the above description, only the case where the connection bumps 11 are provided on only one surface of the insulating protective layer 6 is shown, but the connection bumps 11 may be formed on both surfaces. This is made possible by the formation of the holes 7 and 8. The hole 7 is provided so as to reach the cathode electrode layer 5, the hole 8 is provided so as to reach the anode electrode portion 2, the insulating layer 9 is provided in the hole 8, and these are plated. By forming the conductor 10, a solid electrolytic capacitor having connection bumps 11 on both surfaces can be obtained.

Further, the extraction electrodes 12 and 13 are not always necessary, and the extraction electrodes 12 and 13 are
13 can be used instead, or a semiconductor or chip component mounted on the connection bump 11 can be used as a lead electrode.

Next, an example of a method for manufacturing a solid electrolytic capacitor of the present invention will be described with reference to FIGS. First, FIG.
As shown in (1), an aluminum foil having one surface etched is prepared as a valve metal porous sheet 1. This aluminum foil can be easily obtained by masking one side and etching.

Next, as shown in FIG. 4, an anode electrode portion 2 made of copper is formed on one side of the valve metal porous sheet member 1 made of aluminum foil that has not been etched. The anode electrode portion 2 can be formed by sputtering, vapor deposition, or pasting a copper foil.

Next, as shown in FIG. 5, a resist layer 14 such as a chemically resistant photoresist or masking tape is formed on both sides.
After the resist layer 14 is cured, a necessary number of holes 8 are formed by punching in necessary portions as shown in FIG. 6, and a resin material is formed in the inner wall of the holes 8 as shown in FIG. The insulating layer 9 is formed by electrodeposition.

Subsequently, as shown in FIG. 8, the resist layer 14 on the side opposite to the anode electrode section 2 is peeled off or dissolved and removed to expose the other side of the valve metal porous sheet body 1, To form a dielectric oxide film 3 on the surface and the surface of the pores as shown in FIG. 9, and immerse the formed dielectric oxide film 3 in a solution containing polypyrrole. To form a thin polypyrrole layer on the dielectric oxide film 3 by chemical oxidative polymerization, and immerse the resultant polypyrrole layer in a solution containing polypyrrole to set the polypyrrole layer to the + side and to set the electrodes in the solution to-. By performing electrolytic polymerization on the side, a polypyrrole layer having a sufficient thickness is formed on the polypyrrole layer to form the solid electrolyte layer 4.

Next, as shown in FIG. 10, a resin sheet 15 having a cathode electrode layer 5 made of copper formed on one side thereof is
Was adhered to the solid electrolyte layer 4 so as to be electrically conductive. Subsequently, as shown in FIG. 11, a hole 7 was formed at a predetermined position on the anode electrode portion 2 side, and an opening was formed to communicate with a side surface of the anode electrode portion 2. An insulating protective layer 6 made of an epoxy resin or the like is formed including the side surfaces.

Then, as shown in FIG. 12, a conductor 10 is formed by plating copper or the like on the inner surfaces of the holes 7 and 8 and the opening, and the conductor 10 in the hole 7 is connected to the anode electrode portion 2 and the conductor in the hole 8. The body 10 is formed so as to be electrically connected to the cathode electrode layer 5.

Finally, as shown in FIG. 13, a connection bump 1 made of solder, gold, tin, or silver is formed on the exposed portion of the conductor 10.
1 and at the same time, as shown in FIG. 14, lead electrodes 12, 13 connected to the anode electrode portion 2 and the cathode electrode layer 5, respectively, are formed on the side and bottom surfaces to complete the solid electrolytic capacitor.

As another example, when a sintered body of valve metal powder is used as the valve metal porous sheet body 1, a tantalum sintered body 17 is bonded to one surface of a tantalum foil 16 as shown in FIG. The porous metal sheet 1 is constituted.

In the other steps, the same steps as those in the case of using the aluminum foil having one surface etched are used to manufacture a solid electrolytic capacitor.

[0039]

As described above, since the solid electrolytic capacitor of the present invention is constructed, a semiconductor can be directly connected to the surface on which the connection bumps are formed, so that the high-frequency response is extremely excellent. It can be effective in configuring a digital circuit.

[Brief description of the drawings]

FIG. 1 is a perspective view of a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a cross-sectional view of a valve metal porous sheet used for the solid electrolytic capacitor.

FIG. 4 is a sectional view showing a state in which an anode electrode portion is formed on the valve metal porous sheet body.

FIG. 5 is a cross-sectional view showing a state where resist is formed on both sides of the valve metal porous sheet.

FIG. 6 is a sectional view showing a state in which the hole is formed.

FIG. 7 is a sectional view showing a state where an insulating layer is formed in the hole.

FIG. 8 is a sectional view showing a state where the resist on one side is removed.

FIG. 9 is a cross-sectional view showing a state where a dielectric oxide film and a solid electrolyte layer are formed.

FIG. 10 is a sectional view showing a state where the cathode electrode layer is formed.

FIG. 11 is a sectional view showing a state where the insulating protective layer is formed.

FIG. 12 is a sectional view showing a state where a conductor is formed in the hole.

FIG. 13 is a sectional view showing a state where connection bumps are formed on the conductor.

FIG. 14 is a sectional view showing a state where the extraction electrode is formed.

FIG. 15 is a sectional view showing another valve metal porous sheet body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve metal porous sheet body 2 Anode electrode part 3 Dielectric oxide film 4 Solid electrolyte layer 5 Cathode electrode layer 6 Insulation protection layer 7,8 hole 9 Insulation layer 10 Conductor 11 Connection bump 12,13 Extraction electrode 14 Resist layer 15 Resin Sheet 16 Tantalum foil 17 Tantalum sintered body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Ryo Kimura, Inventor 1006, Oaza Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Koichi Kojima 1006, Oaza Kadoma, Kadoma, Osaka Pref. 72) Inventor Hideki Masumi 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor ▲ Taka ▼ Seiji 1006 Odaka, Kazuma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] An anode electrode portion is provided on one surface of a valve metal porous sheet having a dielectric oxide film formed on a surface and a hole surface, and a solid electrolyte layer and a cathode electrode layer are provided on the other surface of the valve metal porous sheet. Provide an insulating protective layer on these outer peripheral surfaces,
At least one surface of the insulating protective layer is provided with a hole reaching the anode electrode portion and the cathode electrode layer, and a conductor electrically connected to each electrode and insulated from the other is provided in the hole. Solid electrolytic capacitor with connecting bumps on the exposed surface of the conductor. 2. The solid electrolytic capacitor according to claim 1, wherein an aluminum foil having one surface etched is used as the valve metal porous sheet. 3. The solid electrolytic capacitor according to claim 1, wherein a sintered body of valve metal powder is used as the valve metal porous sheet body. 4. The solid electrolytic capacitor according to claim 1, wherein an unetched surface of an aluminum foil having one surface etched is used as the anode electrode portion. 5. The solid electrolytic capacitor according to claim 1, wherein another metal layer formed on an unetched surface of the aluminum foil having one surface etched is used as the anode electrode portion. 6. A method according to claim 1, wherein one side of the sintered body of valve metal powder on which no dielectric oxide film is formed is used as the anode electrode part.
3. The solid electrolytic capacitor according to item 1. 7. The solid electrolytic capacitor according to claim 1, wherein a metal layer formed on one surface of a sintered body of valve metal powder on which a dielectric oxide film is not formed is used as an anode electrode portion. 8. The solid electrolytic capacitor according to claim 1, wherein a functional polymer is used as the solid electrolyte layer. 9. The solid electrolytic capacitor according to claim 1, wherein a manganese dioxide layer is used as the solid electrolyte layer. 10. The solid electrolytic capacitor according to claim 1, wherein the number of connection bumps is equal to or greater than the number of semiconductor connection bumps.